This invention relates to heating containers and, more particularly, to a handy heating container in which food or drink, canned or otherwise, to be heated, such as "sake", coffee, soup, or the like, is set ready for being heated.
Conventionally, a fast heating container comprises a storage chamber for a foodstuff or drink contained in a can, and a reaction chamber for heat generation, the chambers being integrally connected. As such, the manufacture of such heating container requires a rather complicated process. Another difficulty with such heating container is that the can for the food or drink cannot be heated.
In view of these difficulties, the present inventors have developed net type fast heating containers which have no particular heating structure provided therein and which, nevertheless, are able to heat cans for foods or drinks. One such heating container is described in Japanese Patent Publication No. 164291 of 1986. This heating container is such that packages of heating mediums, such as quick lime, water, and the like are arranged in the container and a can for a foodstuff or drink is placed on the heating medium packages.
Another such new type heating container developed by the present inventors is described in Japanese Patent Publication No. 238537 of 1986, which represent an improvement over the invention of said Japanese Patent Publication No. 164291 of 1986. This heating container is such that a solution package containing water or a solution consisting principally of water is housed, together with a heat generating material, in a retainer portion, said retainer portion being placed in a container. In one embodiment of the newer invention, the solution package containing water or a solution consisting principally of water is placed on the upper side and the heat generating material is placed on the lower side.
However, the invention of said Japan Pat. publication No. 238537/1986 has a difficulty in that since the solution package is placed above the heat generating material, exothermic reaction progresses downward from the upper portion of the heat generating material when the solution discharge device is manipulated, so that when heat generation has progressed down to the lower portion of the heat generating material, the upper portion of the heat generating material interferes with upward heat transfer from the lower portion of the heat generating material, with the result that the food or drink being heated is not sufficiently heated.
Another difficulty is that if the food or drink in the can is taken before the end of the exothermic reaction, the interior of the retainer portion is overheated to cause a large amount of water vapor to be generated, because the heat is not absorbed into the food or drink. As a consequence, it is very likely that abnormalities, such as water vapor jetting out through the gap between the can and the container or the can being blown off under a large internal pressure, will occur, which involved considerable danger.